Hermetic compressor

ABSTRACT

A hermetic compressor including a cylinder defining a compressing chamber, a piston to rectilinearly reciprocate in the compressing chamber so as to compress a refrigerant, a rotating shaft having an eccentric shaft portion to be eccentrically rotated, and a connecting rod to connect the eccentric shaft portion and the piston to each other so as to convert the eccentric rotation of the eccentric shaft portion into the rectilinear reciprocation of the piston. The connecting rod includes a first coupling portion to be coupled to the eccentric shaft portion, a second coupling portion to be coupled to the piston, and an elastic member having both ends to be secured, respectively, to the first and second coupling portions so as to connect the first and second coupling portions to each other.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 2006-0133763, filed on Dec. 26, 2006 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a hermetic compressor, and, more particularly, to a hermetic compressor which can efficiently reduce wear of a piston or connecting rod and noise caused by a worn piston or connecting rod even upon an initial starting time or when a refrigeration cycle is abnormally overloaded.

2. Description of the Related Art

In general, a hermetic compressor is employed in a refrigeration cycle of a refrigerator or air conditioner, and conventionally includes a hermetic container defining the outer appearance thereof, a compressing unit to compress a refrigerant, and a drive unit to provide refrigerant compressive power, both the compressing unit and the drive unit being arranged in the hermetic container.

The drive unit takes the form of a conventional motor including a stator and a rotor. The compressing unit includes a cylinder defining a compressing chamber therein and a piston to perform rectilinear reciprocating motion in the compressing chamber, for the purpose of compressing a refrigerant.

The power of the drive unit is transmitted to the piston via a rotating shaft. The rotating shaft is press-fitted in the rotor of the drive unit, so as to be rotated together with the rotor. One end of the rotating shaft defines an eccentric shaft portion to be eccentrically rotated. The eccentric shaft portion is connected to the piston via a connecting rod.

The connecting rod takes the form of a single bar having first and second coupling holes formed at opposite ends thereof, respectively. The first coupling hole of the connecting rod is rotatably fitted around the eccentric shaft portion. Also, in a state in which the end of the connecting rod having the second coupling hole is inserted into the piston, a piston pin is fastened into the piston and the second coupling hole. In this way, connection of the eccentric shaft portion and the piston is accomplished.

With the above described configuration, if electric current is applied to the stator of the drive unit, the rotor is rotated via electromagnetic interaction between the stator and the rotor, and simultaneously the rotating shaft press-fitted in the rotor is rotated together with the rotor. Thereby, according to eccentric rotation of the eccentric shaft portion, the piston, which is connected to the eccentric shaft portion via the connecting rod, rectilinearly reciprocates in the compressing chamber, so as to compress a refrigerant.

A problem of the above described conventional hermetic compressor is that the piston may shake violently if an excessive load pressure is applied in an instant to a tip end of the piston upon an initial starting time or when the refrigeration cycle is abnormally overloaded. If the piston shakes violently, the connecting rod connected to the piston also vibrates. Consequently, the piston as well as the connecting region between the end of the connecting rod and the piston suffer from excessive wear and generation of serious noise.

SUMMARY OF THE INVENTION

Therefore, it is an aspect of the disclosure to provide a hermetic compressor which can efficiently reduce wear of a piston or connecting rod and noise caused by a worn piston or connecting rod upon an initial starting time or when a refrigeration cycle is abnormally overloaded.

In accordance with an aspect, an exemplary embodiment of the hermetic compressor comprises a cylinder defining a compressing chamber, a piston to rectilinearly reciprocate in the compressing chamber so as to compress a refrigerant, a rotating shaft having an eccentric shaft portion to be eccentrically rotated, and a connecting rod to connect the eccentric shaft portion and the piston to each other so as to convert the eccentric rotation of the eccentric shaft portion into the rectilinear reciprocation of the piston, wherein the connecting rod comprises a first coupling portion to be coupled to the eccentric shaft portion, a second coupling portion to be coupled to the piston, and an elastic member having both ends to be secured, respectively, to the first and second coupling portions so as to connect the first and second coupling portions to each other.

The elastic member may include a coil spring.

The connecting rod may further comprise an anti-distortion member to prevent mutual distortion of the first and second coupling portions.

The anti-distortion member may comprise a fixing portion formed at one end thereof so as to be fixed to any one of the first and second coupling portions, and an insert portion formed at the other end thereof so as to be inserted into an insertion recess formed in the remaining one of the first and second coupling portions, the insert portion being adapted to move forward or rearward in the insertion recess according to expanding and contracting operations of the elastic member.

The insert portion and the insertion recess may be configured to prevent mutual relative rotation thereof.

The insert portion may have a polygonal cross section, and side surfaces of the insert portion may come into close contact with the insertion recess.

The insert portion may be located inside the insertion recess in a state in which no external force is applied to the elastic member.

The elastic member may be a coil spring, and the anti-distortion member may be installed through the interior of the elastic member.

Additional aspects and/or advantages of the hermetic compressor will be set forth in part in the description.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the exemplary embodiments of the hermetic compressor will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, of which:

FIG. 1 is a sectional view illustrating the general configuration of a hermetic compressor according to a preferred embodiment;

FIG. 2 is a perspective view illustrating the configuration of a connecting rod included in the hermetic compressor according to the preferred embodiment;

FIG. 3 is an exploded perspective view of the connecting rod of FIG. 2;

FIG. 4 is a sectional view of the connecting rod, illustrating a state in which an elastic member performs no shock-absorbing function; and

FIG. 5 is a sectional view illustrating a state in which the elastic member performs a shock-absorbing function.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made in detail to a hermetic compressor according to an exemplary embodiment, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the figures.

As shown in FIG. 1, the hermetic compressor according to the present embodiment includes a hermetic container 10 formed by coupling an upper container 10 a and a lower container 10 b to each other. The hermetic container 10 is provided, at opposite sides thereof, with a suction pipe 11 to guide a refrigerant, passed through an evaporator of a refrigeration cycle, into the hermetic container 10 and with a discharge pipe 12 to guide the refrigerant, compressed within the hermetic container 10, to a condenser of the refrigeration cycle at the outside of the hermetic container 10.

Provided within the hermetic container 10 are a compressing unit 20 to compress a refrigerant, and a drive unit 30 to provide power required to compress the refrigerant. Both the compressing unit 20 and the drive unit 30 are installed via a frame 40.

The drive unit 30 includes a stator 31 secured around an upper portion of the frame 40, and a rotor 32 provided inside the stator 31 and adapted to be rotated via electromagnetic interaction with the stator 31.

The compressing unit 20 includes a cylinder 21 integrally formed at a lower portion of the frame 40 and defining a compressing chamber 21 a therein, a piston 22 installed to rectilinearly reciprocate in the compressing chamber 21 a so as to compress a refrigerant, a cylinder head 23 coupled to an end of the cylinder 21 so as to hermetically seal the compressing chamber 21 a, the cylinder head 23 defining a refrigerant suction chamber 23 b and a refrigerant discharge chamber 23 a therein, and a valve device 24 interposed between the cylinder 21 and the cylinder head 23 to control the flow of the refrigerant being suctioned from the refrigerant suction chamber 23 b into the compressing chamber 21 a or being discharged from the compressing chamber 21 a into the refrigerant discharge chamber 23 a.

Here, the refrigerant suction chamber 23 b serves to guide the refrigerant, introduced into the hermetic container 10 through the suction pipe 11, into the compressing chamber 21 a. The refrigerant discharge chamber 23 a is connected to the discharge pipe 12. Reference numeral 13 denotes a suction muffler to guide the refrigerant, introduced into the hermetic container 10 through the suction pipe 11, into the refrigerant suction chamber 23 b with a reduced pressure pulsation.

To transmit the power of the drive unit 30 to the compressing unit 20, a rotating shaft 50 is installed in the center of the frame 40. The frame 40 has a center through-hole 41 and a journal bearing 42 installed in the through-hole 41 to rotatably support the rotating shaft 50. Specifically, the rotating shaft 50 is press-fitted into the rotor 32 through an upper portion of the journal bearing 42. A lower end portion of the rotating shaft 50, protruding downward from the frame 40, defines an eccentric shaft portion 51 to be eccentrically rotated upon rotation of the rotating shaft 50. The eccentric shaft portion 51 is connected to the piston 22 via a connecting rod 60.

In the above described configuration, if the rotating shaft 50 is rotated together with the rotor 32 via electromagnetic interaction between the stator 31 and the rotor 32, the piston 22, which is connected to the eccentric shaft portion 51 via the connecting rod 60, rectilinearly reciprocates in the compressing chamber 21 a, thereby creating a pressure difference between the interior and the exterior of the compressing chamber 21 a. With the pressure difference, a refrigerant, which is guided into the hermetic container 10 along the suction pipe 11 from the evaporator of the refrigeration cycle, is suctioned into the compressing chamber 21 a by way of the refrigerant suction chamber 23 b of the cylinder head 23, so as to be compressed in the compressing chamber 21 a. Then, the compressed refrigerant is discharged toward the condenser of the refrigeration cycle at the outside of the hermetic container 10 by way of the refrigerant discharge chamber 23 a of the cylinder head 23 and the discharge pipe 12. As the above described process is repeatedly performed, the compression of the refrigerant by the hermetic compressor is accomplished.

Meanwhile, upon an initial starting time or when the refrigeration cycle is abnormally overloaded, an excessive load pressure is applied in an instant to a tip end of the piston 22, thus causing the piston 22 and the connecting rod 60 connected to the piston 22 to shake violently. Thereby, the piston 22 and the connecting rod 60 may cause serious wear and noise. In the hermetic compressor according to the present embodiment, to solve the above problem, the connecting rod 60 is configured to perform a shock-absorbing function.

FIGS. 2 and 3 illustrate the configuration of the connecting rod 60 in detail.

As shown in FIGS. 2 and 3, in the present embodiment, the connecting rod 60 includes a first coupling portion 61 to be coupled to the eccentric shaft portion 51, a second coupling portion 62 to be coupled to the piston 22, and an elastic member 63 to connect the first coupling portion 61 and the second coupling portion 62 to each other.

Specifically, the first coupling portion 61 has a first coupling opening 61 a to be rotatably fitted around the eccentric shaft portion 51. The second coupling portion 62 has a second coupling opening 62 a. If the second coupling portion 62 is inserted into a rear region of the piston 22, a piston pin 22 a is fastened into the piston 22, and subsequently fitted into the second coupling opening 62 a, so as to connect the second coupling portion 62 to the piston 22. The elastic member 63 is a coil spring having both ends secured to the first coupling portion 61 and the second coupling portion 62, respectively. Here, the first coupling portion 61 and the second coupling portion 62 each has a coupling hole 61 b or 62 b, for the coupling of either end of the elastic member 63. Both the ends of the elastic member 63 can be attached to the coupling holes 61 b and 62 b by welding, bonding, etc.

Accordingly, in a state in which the eccentric shaft portion 51 and the piston 22 are connected to each other via the connecting rod 60, even if an excessive load pressure is applied to a tip end of the piston 22 upon an initial starting time or when the refrigeration cycle is abnormally overloaded, the elastic member 63 acts to buffer and absorb the load pressure applied to the piston 22 by being contracted from the state shown in FIG. 4 to the state shown in FIG. 5. This efficiently prevents any shaking of the piston 22 or connecting rod 60, thereby restricting wear of the piston 22 or connecting rod 60, and consequently generation of noise.

As a result of connecting the first coupling portion 61 and the second coupling portion 62 of the connecting rod 60 to each other via the elastic member 63 performing the shock-absorbing function, the connecting rod 60 can efficiently absorb an excessive pressure load applied to the piston 22 while guaranteeing a simplified configuration thereof.

In a state in which the first coupling portion 61 and the second coupling portion 62 are connected to each other via the elastic member 63 in the form of a coil spring, however, there is the risk of mutual distortion of the first coupling portion 61 and the second coupling portion 62 as the elastic member 63 is elastically deformed to absorb the load pressure applied to the piston 22. Accordingly, to prevent the mutual distortion, the connecting rod 60 is provided with an anti-distortion member 64, to prevent the mutual distortion of the first coupling portion 61 and the second coupling portion 62 without hindering the expanding and contracting operations of the elastic member 63. The anti-distortion member 64 is installed in the interior of the elastic member 63 in the form of the coil spring, so as not to occupy a separate installation space.

The anti-distortion member 64 has a linear bar shape. One end of the anti-distortion member 64 is provided with a fixing portion 64 a to be fixedly coupled into the first coupling portion 61, and the other end of the anti-distortion member 64 opposite to the fixing portion 64 a is provided with an insert portion 64 b to be inserted into the second coupling portion 62.

The first coupling portion 61 has a fixing recess 61 c for the coupling and fixing of the fixing portion 64 a. The fixing portion 64 a is inserted into the fixing recess 61 c and fixedly mounted by welding, bonding, etc.

The second coupling portion 62 has an insertion recess 62 c for the insert portion 64 b. The insert portion 64 b is configured to be inserted into the insertion recess 62 c such that it is forwardly or rearwardly movable according to the expanding and contracting operations of the elastic member 63 without interference with the shock-absorbing operation of the elastic member 63. Preferably, even when no external force is applied to the elastic member 63, the insert portion 64 b is located in the insertion recess 62 c so as not to be separated from the insertion recess 62 c during the installation of the connecting rod 60.

Both the insert portion 64 b and the insertion recess 62 c are configured to prevent mutual relative rotation thereof, to restrict the distortion of the first coupling portion 61 and the second coupling portion 62.

For this, in the present embodiment, the insert portion 64 b has a rectangular cross section, and the insertion recess 62 c has a rectangular cross section corresponding to that of the insert portion 64 b. In particular, side surfaces of the insert portion 64 b are configured to come into close contact with corresponding inner wall surfaces of the insertion recess 62 c. This configuration is to prevent the relative rotation of the insert portion 64 b and the insertion recess 62 c.

Of course, it will be appreciated that the cross section of the insert portion 64 b and the insertion recess 62 c may be changed into other various shapes, for example, polygonal shapes including triangular and pentagonal shapes, so long as the cross section of the insertion recess 62 c corresponds to the cross section of the insert portion 64 b and the relative rotation of the insert portion 64 b and the insertion recess 62 c can be prevented. Alternatively, conversely to the present embodiment, the anti-distortion member 64 may be configured such that one end thereof facing the second coupling portion 62 defines a fixing portion and the other end thereof facing the first coupling portion 61 defines an insert portion that is inserted into the first coupling portion 61 in a forwardly or rearwardly movable manner without rotation.

As apparent from the above description, according to an exemplary embodiment of a hermetic compressor, a connecting rod has a first coupling portion to be coupled to an eccentric shaft portion of a rotating shaft, and a second coupling portion to be coupled to a piston, and the first coupling portion and the second coupling portion are connected to each other via an elastic member.

Accordingly, with the exemplary embodiment of the hermetic compressor, even if an excessive load pressure is applied to a tip end of a piston upon an initial starting time or when a refrigeration cycle is abnormally overloaded, the load pressure can be buffered and absorbed via the expanding and contracting operations of the elastic member. Thereby, it is possible to efficiently prevent the shaking of the piston or connecting rod, and consequently, to restrict the wear of the piston and the connecting rod and the generation of noise.

Although an exemplary embodiment has been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A hermetic compressor comprising a cylinder defining a compressing chamber, a piston to rectilinearly reciprocate in the compressing chamber so as to compress a refrigerant, a rotating shaft having an eccentric shaft portion to be eccentrically rotated, and a connecting rod to connect the eccentric shaft portion and the piston to each other so as to convert the eccentric rotating motion of the eccentric shaft portion into the rectilinear reciprocating motion of the piston, wherein the connecting rod comprises a first coupling portion to be coupled to the eccentric shaft portion, a second coupling portion to be coupled to the piston, and an elastic member having both ends to be secured, respectively, to the first and second coupling portions so as to connect the first and second coupling portions to each other.
 2. The hermetic compressor according to claim 1, wherein the elastic member includes a coil spring.
 3. The hermetic compressor according to claim 2, wherein the connecting rod further comprises an anti-distortion member to prevent mutual distortion of the first and second coupling portions.
 4. The hermetic compressor according to claim 3, wherein the anti-distortion member comprises a fixing portion formed at one end thereof so as to be fixed to any one of the first and second coupling portions, and an insert portion formed at the other end thereof so as to be inserted into an insertion recess formed in the remaining one of the first and second coupling portions, the insert portion being adapted to move forward or rearward in the insertion recess according to expanding and contracting operations of the elastic member.
 5. The hermetic compressor according to claim 4, wherein the insert portion and the insertion recess are configured to prevent mutual relative rotation thereof.
 6. The hermetic compressor according to claim 5, wherein the insert portion has a polygonal cross section, and side surfaces of the insert portion come into close contact with the insertion recess.
 7. The hermetic compressor according to claim 4, wherein the insert portion is located inside the insertion recess in a state in which no external force is applied to the elastic member.
 8. The hermetic compressor according to claim 4, wherein the elastic member is a coil spring, and the anti-distortion member is installed through an interior of the elastic member. 